<!doctype html>
<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <script src="https://cdn.tailwindcss.com"></script>
    <title></title>
    <script>
        // https://blog.csdn.net/weixin_44198965/article/details/107735243 vertical-align剧中实现
    </script>


</head>
<body>
<div style="">
    <div class="wrapper">
        <div class="box"></div>
        <div class="help"></div>
    </div>
</div>

</body>

<style>
    .wrapper{
        width: 500px;
        height: 500px;
        background-color: pink;
        text-align: center;
    }

    .box{
        width: 100px;
        height: 100px;
        background-color: deepskyblue;
        display: inline-block;
        vertical-align: middle;
        margin: 0 auto;
    }

    .help{
        width: 0;
        height: 100%;
        display: inline-block;
        vertical-align: middle;
    }

</style>
</html>